Have you already tried telephone activation? If not;
1. Open any Office application, and select File > Account > activate now
2. Use the telephone activation to activate Office as mentioned in the Activate Office help section.
“Telephone Activation is no longer supported error”
Sometimes when trying to activate Office, you’ll be presented with this error.
Microsoft is currently working on fixing this error, however, they have released a temporary workaround. (https://support.office.com/en-us/article/-Telephone-activation-is-no-longer-supported-for-your-product-error-when-activating-Office-9b016cd2-0811-4cb3-b896-5a6a13177713?ui=en-US&rs=en-US&ad=US)
1. Open any Office program. For example, open Microsoft Word.
2. In the Microsoft Office Activation Wizard, choose I want to activate the software by telephone, then click next.
3. Call the Microsoft Product Activation Center: 888-571-2048
4. Call the Product Activation center and Provide the “installation ID” found in Step 2.
5. The system will ask you, “How many computers has this been installed on?” The correct answer is “1.”
6. Put the ‘confirmation id’ into “Step 3” of the process, and click “next.” Office should now be activated!
Almost all problems and error codes associated with installing Office are due to multiple versions of Office being installed on the same computer.
To quickly and easily fix these issues, run the OFFICE FIX IT TOOL found here: https://aka.ms/diag_officeuninstall
Still having problems? Go to Microsoft’s Help-Page found here: https://support.office.com/en-us/article/Download-and-install-or-reinstall-Office-365-or-Office-2016-on-your-PC-or-Mac-4414eaaf-0478-48be-9c42-23adc4716658?ui=en-US&rs=en-US&ad=US